Airlines and aircraft manufacturers are already heavily incentivized to be fuel efficient. It's the most expensive part of a flight. (Sometimes crew salaries are more expensive but not by much.)

The difference here is between incremental improvements using incremental funding and glacier-speed if any of regulatory framework evolution vs. crisis situation changing calculus and providing option for large funding for the previously perceived far-off alternatives as well as jolts to change regulatory frameworks. And i'm not talking just about airplanes.